Systemd tip.

With systemd, services can be socket-activated, D-Bus-activated or manually started.
This means you have to be very cautious when stopping a service and take extra precaution if you don’t want it to restart!
Previously with RHEL 6, to stop the NetworkManager service for example, you had to type:

# service NetworkManager stop; chkconfig NetworkManager off

In the new RHEL 7 world, you will have to type:

# systemctl disable NetworkManager; systemctl stop NetworkManager

It’s disable then stop and not the other way around!
If you don’t follow this rule, you will be sometimes surprised to see your service still running: it will have been restarted by another process!
This is a true story that happened with the NetworkManager service.
Be assured this will happen again if you are not careful!